Method for manufacturing fin field effect transistor

Abstract

The invention provides a method for manufacturing a fin field effect transistor. The method includes forming a grid hard mask used for positioning a grid and a side wall hard mask surrounding the side face of the grid hard mask on a semiconductor substrate; by utilizing the side wall hard mask as a self-aligning hard mask, enabling the semiconductor substrate to form first fin structures with inclined side faces, forming shallow groove isolators among the first fin structures , removing the side wall hard mask, performing second-time etching, and finally acquiring the fin field effect transistor where the upper portion and the lower portion are different in width. The side faces of the fin structures are inclined when the shallow groove isolators are formed in a filling oxidation layer, so that filling process windows are increased, filling gaps are reduced, and device performance is improved.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for manufacturing a fin field effect transistor. Background technique [0002] In order to keep up with the pace of Moore's Law, people have to continue to shrink the feature size of MOSFET transistors. Doing so can bring benefits such as increasing chip density and improving the switching speed of MOSFETs. As the feature size (CD, Critical Dimension) of the device further decreases, the channel length of the device is shortened, and the distance between the drain and the source is also shortened, so that the control ability of the gate to the channel becomes worse, and the gate voltage It is more and more difficult to pinch off the channel, so that the phenomenon of subthreshold leakage (Subthreshold leakage), the so-called short-channel effect (SCE: short-channel effects) is more likely to occur. [0003] For this reason, the planar CMOS transistor is gradu...

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Problems solved by technology

[0006] Since part of the vertical fins on the fin structure 12 is not conducive to the filling of the oxide, there are gaps 15 in the shallow trench isolation 11, which obviously will greatly reduce the stability of the device.

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